Mindmap

Noradrenaline / Adrenaline

Elly Scanlon Englisch

Inhalt der Mindmap

Produced by sympathetic nerves and adrenal medulla
- Adrenal cortex produced adrenaline
  - Adrenaline = similar to stimulating sympathetic nerves
Parasympathetic
- Nerves coming from brain and sacral parts of spinal cord
Sympathetic
- Nerves coming from thoracic and lumber parts of spinal cord
- Fight/flight
- Gut
  - Decreased motility
  - Increased sphincter tone
- Heart
  - Increased rate and force of attraction
- Iris
  - Pupil dilation
- Liver
  - Glycogen --> glucose
- Adrenal medulla
  - Increase adrenaline production
- Two neurones
  - Pre
  - Post
    - Releases Noradrenaline
      - and ATP
    - Branch in the periphery
Enteric
Synthesis of catecholamines
- Tyrosine
  - E - Tyrosine hydroxylase
    - Dihydroxyphenylalanine
      - E - DOPA decarboxylase
        Dopamine
        E- dopamine beta hydroxylase
        Noradrenaline
        E - Phenylethanolamine N-methyl transferase
        Adrenaline
        Only present in adrenal medulla
        Why neurones only produce Nad
        PNMT
        Increasing amount inhibits Tyrosine Hydroxylase
        Centrally acting NTM
        Inhibited by carbidopa
        Used clinically for parkinsons
        To prevent dopamine for being formed in the periphery
        stays in the brain
      - DOPA
        Treatment for parkinsons
    - Rate limiting step
    - Inhibited by alpha methyltyrosine
Storage
- NAd and Ad = stored in membrane limited particles
  - Chromaffin granules
  - Small vesicles = 50nm
    - Varicosities
  - Large vesicles = 80nm
    - Cell body, axon and varicosities
  - VMAT takes dopamine into vesicles
    - Requires H+
      - H+ out Catech in
        Therefore vesicles have H+ pump
        ATPase
    - Dopamine --> noradrenaline inside vesicle
    - Inhibitor of VMAT
      - Reseprine
        Neurotransmitter release decreases
        Good
        Reduces hypertension
        Decreased sympathetic nerve stimulation to heart
        Bad
        Effects CNS
        Leads to depression
  - VNUT
    - Allows ATP entry
Exocytosis
- Action potential
  - Depolorisation
    - Ca2+ entry
      - Activation of ca2+ sensitive proteins
        Vesicles fuse with nerve terminal
        Release of contents
- Could effect any of the mechanisms to the left
  - Would effect all nerve terminals
- Release of NAd and chromagrannin but no lipid release
  - Supports vesicle rellease
- Botulinum effects exocytosis
- Prejunctional regulation of Ex
  - Alpha 2 receptors on nerve terminal
    - Feedback mechanism
  - ACh receptors
  - Opiate receptors
    - Present on autonomic nerve terminals
      - Inhibit NA release
Termination
- Uptake
  - Into the presynaptic nerve terminal
    - Uptake 1
    - NAT
      - Selective from Nad
      - Can be inhibited
        Antidepressents
        Cocaine
        Also local anaesthetic
        Noradrenaline hangs around for longer
        Activates receptors
        Amplification of sympathetic activity
      - Closely related to dopamine and serotonin transporter
        How they effect depression
  - Into other cells
    - Uptake 2
      - Muscle cellls
      - Endothelium
- Degradation
  - Monamine oxidases and COMT degrade catech
    - Targeted with drugs
      - Inhibitors enhance effects of noradrenaline
    - MAO
      - Drugs treat depression
        Amplify cat in the brain
    - COMT
      - Treat parkinsons
    - Metabolite = VMA
      - Can measure this in the urine
Noradrenergic neuron blocking drugs
- Inhibit noradrenaline release from Sym NT
  - Inhibit ONLY symp
    - As are substrates for NAT
      - Transported into the nerve terminal
Indirectly acting sympathetic amines
- Uptaken by VMAT
  - Displace NAd
    - Release of Nad
      - Similar effect on dopamine and 5-HT in CNS
      - Activates the receptors
  - Enter vesicles
- Enter nerve terminals

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Beschreibung: Mindmap am Noradrenaline / Adrenaline, erstellt von Elly Scanlon am 01/04/2017.
Erstellt von: Elly Scanlon
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